U.S. patent number 4,043,775 [Application Number 05/644,656] was granted by the patent office on 1977-08-23 for air lock filter system.
This patent grant is currently assigned to Ecolaire Inc.. Invention is credited to Richard L. Solomon.
United States Patent |
4,043,775 |
Solomon |
August 23, 1977 |
Air lock filter system
Abstract
There is disclosed an air lock filter system for separating
solids from gases at temperatures up to about 1200.degree. F.
wherein the filter element is a rigid porous refractory tube in an
air vent for a pressure vessel. The filter element is located so
that gas under pressure introduced into the vessel backwashes the
filter element.
Inventors: |
Solomon; Richard L.
(Selinsgrove, PA) |
Assignee: |
Ecolaire Inc. (Philadelphia,
PA)
|
Family
ID: |
24585836 |
Appl.
No.: |
05/644,656 |
Filed: |
December 29, 1975 |
Current U.S.
Class: |
55/302; 55/504;
406/169; 55/431; 55/523; 406/172 |
Current CPC
Class: |
B01D
46/2411 (20130101); B01D 46/4272 (20130101); B01D
46/0068 (20130101); B01D 2273/20 (20130101) |
Current International
Class: |
B01D
46/24 (20060101); B01D 046/04 () |
Field of
Search: |
;55/429,432,301-303,500,504,341,431,310-312 ;210/333,323
;214/17R,17C,17D,17DA ;302/53,54,57 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2,058,422 |
|
May 1971 |
|
FR |
|
1,395,983 |
|
May 1975 |
|
UK |
|
Primary Examiner: Nozick; Bernard
Attorney, Agent or Firm: Seidel, Gonda & Goldhammer
Claims
I claim:
1. An air lock filter system comprising a pressure vessel having a
materials inlet at an elevation above the elevation of a materials
outlet from said pressure vessel, a housing supported adjacent the
upper portion of said vessel and having a dirty gas inlet and a
vent outlet, said dirty gas inlet communicating with the upper end
of said vessel, a first valve means operatively connected to said
housing by way of said vent outlet for selectively venting the
housing and for connecting the housing to a source of gas under
pressure, second valve means for controlling the inlet and outlet
of said pressure vessel, a hollow filter tube in said housing
arranged so that the interior of said tube communicates at one end
with said vent outlet and thereby with said first valve means,
means closing the other end of said tube, said tube being a rigid
porous refractory, and means supporting said tube in said housing
to prevent gas passing through said housing from by-passing said
filter tube so that the outer periphery of said tube is exposed to
gas entering the housing by way of said dirty gas inlet, whereby
gas will be filtered through the outer periphery of said tube into
the interior thereof.
2. A system in accordance with claim 1 wherein said filter tube and
housing are vertically disposed, and said means closing the other
end of said tube being a part of the means for supporting said tube
within said housing.
3. A system in accordance witgh claim 1 including a means for
applying pressure in an axial direction on said tube against an end
face thereof by way of said means closing said tube in order to
support said tube within said housing.
4. A system in accordance with claim 1 wherein said tube is coaxial
with said inlet and said outlet of said housing.
5. A system in accordance with claim 1 wherein said tube is made
from a material capable of withstanding temperatures up to about
1200.degree. F.
6. A system in accordance with claim 1 including a source of
pressurized gas communicating with the outlet of said pressure
vessel.
7. A system in accordance with claim 1 wherien only one filter tube
is disposed within said housing.
8. A system in accordance with claim 7 wherein said one filter tube
is comprised of a rigid, porous refractory material having an axial
length of approximately 18 inches, an outer diameter of
approximately 8 inches and an inner diameter of approximately 6
inches.
9. A system in accordance with claim 1 including a means for
supplying pressurized gas to said first valve means, whereby said
pressurized gas backwashes said filter tube and pushes material
downwardly within said pressure vessel.
10. A system in accordance with claim 9 including a source of
pressurized gas communicating with the outlet of said pressure
vessel, the pressure of the gas from said means supplying gas to
said first valve means being greater than the pressure of the gas
communicating with the outlet of said pressure vessel.
11. A system in accordance with claim 1 wherein the size of said
housing is substantially less than the size of said pressure
vessel.
Description
BACKGROUND
An air lock device is used to gravity dry, free-flowing materials
from one pressure zone to another. It is used, for example, to
transmit material from an overhead collection point to a
pressurized pneumatic conveying system pipeline without employing
boiler flue gases as a conveying medium and without causing
reentrainment of the material into the gas stream.
The air lock device includes a valve which isolates a bottom vessel
from an upper vessel and a valve which isolates the bottom vessel
from the conveying pipeline. Another valve on the upper vessel
controls the introduction of materials thereinto. When materials
are introduced into the upper vessel, the upper vesel must be
vented to atomosphere so as to permit air to escape. Material is
discharged from the upper vessel to the lower vessel by introducing
a gas into the upper vessel at an elevation above any materials
therein and at a pressure greater than the pressure of the
conveying pipeline.
It is necessary to provide the air vent with a filter system to
preclude the escape of high temperature dry, free-flowing
materials. The problem is to prevent such discharge of materials to
the surrounding atmosphere or into other parts of the system while
at the same time having a filter element which requires little or
no maintenance, can withstand the temperatures involved, and is
readily accessible while at the same time will permit flow in
opposite directions.
DISCLOSURE
The present invention is directed to an air lock filter system
which includes a housing having a dirty gas inlet and a vent
outlet. A valve means is operatively connected to the housing by
way of the vent outlet for selectively venting the housing to
atmosphere and for selectively connecting the housing to a source
of gas under pressure. A filter element in the form of a rigid
hollow tube of refractory material is supported in the housing and
arranged so that the interior of the tube communicates at one end
with one of said outlet and inlet. A means is provided for closing
the other end of the tube. The periphery of said tube is exposed to
gas entering the housing by way of said inlet which is adapted to
be connected to a pressure vessel.
Any of the particulate which ordinarily would escape when the
pressure vessel is vented to atmosphere will be trapped by the
filter element. When the pressure vessel is being pressurized, the
pressurized gas is introduced through said one end of said filter
element to thereby simultaneously backwash the filter element.
Hence, the air lock filter system of the present invention
automatically attains a backwash when the pressurized gas is
introduced into the pressure vessel to affect a discharge of
material from the pressure vessel.
It is an object of the present invention to provide a novel air
lock filter system.
It is another object of the present invention to provide an air
lock filter system which utilizes a rigid porous refractory tube as
a filter element for separating solids from gases at temperatures
up to about 1200.degree. F.
It is another object of the present invention to provide an air
lock filter system which is orientated so that it will
automatically be backwashed when air is introduced into a pressure
vessel to effect discharge of contents from the pressure
vessel.
Other objects will appear hereinafter.
For the purpose of illustrating the invention, there is shown in
the drawings a form which is presently preferred; it being
understood, however, that this invention is not limited to the
precise arrangements and instrumentalities shown.
FIG. 1 is a vertical sectional view of a system in accordance with
the present invention.
FIG. 2 is a vertical sectional view of the air lock filter on an
enlarged scale.
Referring to the drawing in detail, wherein like numerals indicate
like elements, there is shown in FIG. 1 a system in accordance with
the present invention designated generally as 10.
An upper vesel 12 is connected to a lower vessel 14 by way of a
deck plate 16 containing an opening controlled by a selectively
operable valve 18. The valve 18 is preferably a sliding gate
valve.
The upper vessel 12 is preferably cone-shaped at its lower end and
provided at its upper end with an inlet 20. The inlet 20 is
controlled by a selectively operable valve member 22. Valve member
22 is preferably a sliding gate valve moved between operative and
inoperative positions by an air cylinder 24 mounted on the top deck
plate 26. Vessel 12 may be provided with an access panel 28 in a
side wall thereof if desired.
The bottom vessel 14 is provided with a intake tee 32 which
communicates with a conveying pipeline 30. The conveying pipeline
30 is at a pressure between 3 and 14 psi and may be utilized to
convey a mixture of solids and liquids to a silo or other storage
area. A selectively operable valve 34 is provided between the
intake tee 32 and the lower end of the cone-shaped bottom of vessel
14. Valve 34 is preferably a metering and cut-off slide gate
valve.
The upper end of the upper vessel 12 is vented to atmosphere by way
an air lock filter connected to conduit 36. Conduit 36 is removably
connected to inlet 38 on the lower end of a housing 40. The upper
end of the housing 40 is provided with a cover 42 containing an
outlet port 44. Flow through the outlet port 44 is controlled by a
valve 46.
The valve 46 includes a threaded port 48 adapted to be vented
directly to atmosphere and a threaded port 50 adapted to be
connected to a source of gas under pressure. Each of the ports 48
and 50 selectively communicate with the valve chamber 52 which in
turn is directly in communication with the outlet port 44.
Flow between port 50 and chamber 52, as illustrated in FIG. 2, is
closed by a valve element 54. Element 54 is connected to a piston
rod 56 which in turn is connected to a piston within cylinder 58.
When the piston rod 56 and valve element 54 are moved from left to
right in FIG. 2, port 50 communicates directly with chamber 52
while at the same time element 54 will interrupt the communication
between chamber 52 and the port 48. Thus, valve member 54
selectively closes one of a pair of aligned openings so that only
one of the ports 48, 50 communicates with chamber 52 at any given
time.
As shown more clearly in FIG. 2, there is provided within the
housing 40 a filter element 60. the filter element 60 is a rigid
porous refractory tube having an axial length of about 18 inches.
The length of the tube 60 may be varied as desired. Tube 60
preferably has an OD of 8 inches and an ID of 6 inches. These
diameters may be varied as desired. A wide variety of materials
maybe utilized for the tube 60.
The tube 60 in the preferred embodiment of the present invention is
made from a porous refractory material sold commercially under the
trademark ALUNDUM by the Refractory Division of the Norton Company,
Worcester, Massachusetts. A typical chemical analysis of said
ALUNDUM material is as follows:
Al.sub.2 O.sub.3 : 82%
SiO.sub.2 : 13
Fe.sub.2 O.sub.3 : 1.0
MgO: 0.5
CaO: 0.8
Na.sub.2 O: 0.2
TiO.sub.2 : 2.5 MnO: trace.
The upper end of the tube 60 circumscribes the outlet port 44 and
is sealed to the lower surface of the cover 42 by a sealant. The
lower end of the tube 60 is closed in any convenient manner such as
by a bottom plate 62. A sealant is preferably provided between the
plate 62 and the lower end face of the tube 60. Plate 62 is
supported within the housing 40 by way of a plurality of adjustable
tie rods 64 connected at their upper end to the cover 42 to thereby
provide a means for supporting the tube 60 within the housing 40.
If desired, a ring-like collar may be provided on the lower surface
of cover 42 and the upper surface of plate 62 to act as a guide for
the ends of the tube 60 to prevent the ends from shifting. The
housing 40 may be provided with a sight panel to facilitate
obseravation of the components disposed therewithin. All of the
components of the system disclosed herein are made of high
temperature resistant materials including the filter element which
can withstand temperatures up to about 1200.degree. F.
The system 10 operates as follows.
Valve 34 is normally open and is closed for maintenance purposes.
Valve 18 is closed and valve 22 is open. Valve 46 is in the
position shown in FIG. 2. Dry, free-flowing material such as fly
ash at a temperature of 1000.degree. F. is introduced by a gravity
feed into the upper vessel 12 by way of inlet 20. Air within the
upper vessel 12 which is displaced by the material is vented by way
of port 48 to the atmosphere. Any of the material which tends to
flow from the upper vessel 12 to the port 48 is filtered out as the
air flows into the tube 60.
When the desired amount of material is provided within the upper
chamber 12, valve 22 is closed, valve 18 is opened, and valve 46 is
shifted so that valve element 54 closes off the port 48. This
results in port 50 being in communication with the space above the
material within the upper vessel 12 by way of housing 40 and
conduit 36. Gas under pressure, which is preferably about 1 to 11/2
pounds greater that the pressure in pipeline 30 is introduced from
a source not shown into the space above the material in vessel 12
to push the material downwardly into the bottom vessel 14. The air
or other gas under pressure introduced by way of port 50 acts as a
backwash for the tube 60. Hence, each time a quantity of material
is transferred from the upper vessel 12 to the lower vessel 14, the
filter tube 60 is backwashed by the same air used to effect the
transfer.
Thereafter, valve 18 is closed and valve 34 is opened whereby the
material is introduced into the pipeline 30 for conveyance to any
suitable storage location such as a silo. The transfer tee 32 acts
as a surge chamber.
The present invention may be embodied in other specific forms
without departing from the spirit or essential attributes thereof
and, accordingly, reference should be made to the appended claims,
rather than to the foregoing specification as indicating the scope
of the invention.
* * * * *